In a wire bonding process, for example, in order to bond a wire to a desired position on a bonding target, it is necessary to perform correct positioning of a position of a tip end of a tool holding the wire to the desired position on the bonding target. Although a positioning camera is provided for this purpose, it is not possible to provide the positioning camera at the same position as the bonding tool. Therefore, the bonding tool and the positioning camera are provided with a predetermined offset distance therebetween, positioning is performed between the positioning camera and the desired position on the bonding target, and then the bonding tool is moved by the offset distance.
PTL 1 discloses use of a light source, a reference member, and an optical system such as a prism in order to correctly calibrate an offset amount between a shaft center of a tool of a bonding apparatus and an optical axis of a position detection camera provided separately from the tool. Here, a stick-shaped reference member and a tool tip end are irradiated with light using the light source, shadows of the reference member and the tool tip end are detected by the optical system using a position detection camera, and an offset amount is correctly calibrated based on displacement between the shadows.
PTL 2 discloses a wire connecting apparatus having a diagonal optical system of a configuration in which immediately before a capillary performs pressurization, a connecting area is irradiated with light from an obliquely upward position at a predetermined angle with respect to a direction in which the capillary extends, and an image of the connecting area is taken using a camera provided symmetrically obliquely with the capillary interposed therebetween, instead of a camera taking an image of a connecting area from a vertically upward position. Here, a two-dimensional coordinate of an ideal pressurizing point of the connecting area is specified by the camera, movement of the capillary is stopped when the capillary moves at a searching height, a portion of a tip end of the capillary at this time and its shadow are captured using the camera of the diagonal optical system, a two-dimensional coordinate of a predicted pressurizing point is obtained to obtain a difference between the two-dimensional coordinate of the predicted pressurizing point and the two-dimensional coordinate of the ideal pressurizing point, and thus the movement of the capillary is corrected.